Squamous Cell Carcinoma (SCC) vs. Basal Cell Carcinoma (BCC)

00:02 First off, I think we'll talk about squamous cell carcinoma before coming back to basal cell carcinoma.

00:08 Squamous cell carcinoma, as you may recall typically is on a spectrum of development or evolution starting with actinic keratosis, then squamous cell carcinoma in situ and then squamous cell carcinoma.

00:21 Actinic keratosis are described as these discrete dry, sandpapery, skin colored or yellow-brown papules.

00:31 They're incredibly common, very hard to see just visually until you reach in closely, look closely at the skin and rub your fingers on the lesion and you'll feel that sandpapery lesion especially on the scalp of folks who are balding or bald or on the backs of the hands.

00:49 One percent of actinic keratosis will evolve into squamous cell carcinoma in situ per year.

00:57 So, if you got 50 of them, there's a 50% chance that one of those might evolve into squamous cell carcinoma in situ each year.

01:05 When you've got squamous cell carcinoma in situ especially a background of several of them these well-demarcated pink, scaly patches it's called Bowen’s disease and a minority of these squamous cell carcinoma in situ lesions can evolve into squamous cell carcinoma itself which, of course, is more malignant and can be aggressive.

01:26 So, a number of different subtypes of squamous cell carcinoma we'll talk about them in a minute and these can be eroded, friable, hyperkeratotic papules or plaques or nodules.

01:38 So, a lot of different varieties of squamous cell carcinoma to be mindful of.

01:44 The risk factors for squamous cell carcinoma and actinic keratosis are things we've talked about: fair complexion, folks who have chronic wounds in a certain area squamous cell carcinoma in situ may develop within those chronic wounds chronic sun exposure like being a farmer HPV, again keeps showing up in different places as a cause of different types of skin lesions including squamous cell carcinoma and smoking history also plays a role.

02:12 So, here's the subtypes.

02:14 We have the nodular type shown here in the top right.

02:18 Exophytic type which is more representative of the picture down there at the bottom.

02:23 Again, exophytic means growing out of the skin.

02:26 Verrucous which is not shown here and then a cutaneous horn which is this hyperkeratinized plug that can grow out of a lesion and it's very firm, very hard.

02:41 As we discussed with melanoma, if a patient starts to describe pain or paresthesias like pruritus within their lesion that may signify deeper invasion into the dermis and perineural invasions that may be a bad prognostic sign.

02:55 You're going to diagnose this by performing a shave biopsy or perhaps a punch biopsy.

03:00 The treatment is going to depend on if you've got actinic keratosis or if you actually have skin cancer.

03:06 Actinic keratosis and squamous cell carcinoma in situ you can get by with just cryosurgery just basically freezing the lesion.

03:13 You can use 5-FU cream or imiquimod cream and just close observation over time.

03:19 Once you've developed into a squamous cell carcinoma you're going to need to perform an excision and you may or may not need to use Mohs surgery depending upon the type of lesion that you have.

03:30 Now, let's talk about basal cell carcinoma the other type of non melanoma skin cancer and it also happens to be the most common type of skin cancer.

03:39 You really have to make sure you know this one.

03:41 It's locally invasive and aggressive.

03:44 However, it's actually relatively benign insofar as it rarely metastasizes.

03:49 So, you may find patients who have basal cell carcinoma but it's not an emergency.

03:54 You certainly want to get it dealt with and get it resected.

03:56 But it's not something where you're very concerned about long term outcomes as you would for melanoma.

04:02 Ninety percent of the time, they occur on the face.

04:05 Our patient’s got it on his nose, so let's keep that in mind.

04:10 Multiple different subtypes again, and you’d have to just be familiar with the names here when you're thinking about the board exam but the subtypes are the superficial multicentric which is shown here in the top picture.

04:22 Pigmented, again, these can be very black, brown, dark reddish lesions as you're seeing here in number two.

04:30 Ulcerating lesion which can have rolled borders and a central hollowing out ulcerated area.

04:37 Not shown here is the sclerosing subtype.

04:40 Then the nodular subtype, we'll see on the next slide.

04:44 Here's our nodular subtype, which again, is you're going to feel a palpable subdermal indurated area it's going to have some telangiectesias on the skin and there may be an ulcerated area in the middle as well.

04:57 The nodular and ulcerating subtypes are pretty similar to one another.

05:02 Going back to look at our patient, there's no evidence of pruritus and that's pretty typical for basal cell carcinoma lesions.

05:10 This patient spends most of his day in sun-exposed areas.

05:14 So, we're thinking about any kind of skin cancer and basal cell carcinoma would be one of the more common types.

05:19 Again, a dome-shaped, pearly, translucent papule on the tip of the nose, on the face, as we mentioned with visible telangiectesias and probably some somewhat rolled-up borders.

05:31 This is really a very good example of a nodular type of basal cell carcinoma.

05:36 With all that information in mind I think we can safely say that our patient has a basal cell carcinoma presumably the nodular subtype.

05:45 Let's just review a few key points about basal cell carcinoma.

05:49 As I said, it's the most common skin cancer.

05:51 It's locally invasive and aggressive but rarely metastasizes and 90% of the time, it is on the face.

05:57 Treatment is going to be excision.

06:00 You don't typically need to use Mohs surgery because again, it's not a very aggressive lesion in terms of distant metastasis or recurrence.

06:08 You can use electrodessication and curettage as well.

06:11 Shown there on the right is a reminder of our five different subtypes.